Front-end: Add missing rule for function-return implicit type conversion check.

Test/baseResults/functionSemantics.frag.out

 functionSemantics.frag
 Warning, version 400 is not yet complete; most version-specific features are present, but some are missing.
+ERROR: 0:74: 'return' : cannot convert return value to function return type 
+WARNING: 0:74: 'return' : type conversion on return values was not explicitly allowed until version 420 
+ERROR: 1 compilation errors.  No code generated.
+
 
 Shader version: 400
-0:? Sequence
+ERROR: node is still EOpNull!
 0:5  Function Definition: foo(i1;i1;i1;i1;i1;i1; (global int)
 0:5    Function Parameters: 
 0:5      'a' (in int)
@@ -195,6 +199,11 @@ Shader version: 400
 0:69          Construct ivec2 (temp 2-component vector of int)
 0:69            Convert float to int (temp int)
 0:69              'F' (temp float)
+0:72  Function Definition: badConv( (global 4-component vector of float)
+0:72    Function Parameters: 
+0:74    Sequence
+0:74      Branch: Return with expression
+0:74        'u' (uniform float)
 0:?   Linker Objects
 0:?     'u' (uniform float)
 
@@ -203,7 +212,7 @@ Linked fragment stage:
 
 
 Shader version: 400
-0:? Sequence
+ERROR: node is still EOpNull!
 0:5  Function Definition: foo(i1;i1;i1;i1;i1;i1; (global int)
 0:5    Function Parameters: 
 0:5      'a' (in int)
@@ -396,6 +405,11 @@ Shader version: 400
 0:69          Construct ivec2 (temp 2-component vector of int)
 0:69            Convert float to int (temp int)
 0:69              'F' (temp float)
+0:72  Function Definition: badConv( (global 4-component vector of float)
+0:72    Function Parameters: 
+0:74    Sequence
+0:74      Branch: Return with expression
+0:74        'u' (uniform float)
 0:?   Linker Objects
 0:?     'u' (uniform float)
 

Test/functionSemantics.frag

@@ -68,3 +68,8 @@ void aggCall()
     float F;
     m(ivec2(F));  // test input conversion of single argument that's an aggregate; other function tests in 120.vert
 }
+
+vec4 badConv()
+{
+    return u;     // ERROR, can change scalar to vector
+}
\ No newline at end of file

glslang/MachineIndependent/ParseHelper.cpp

@@ -1208,6 +1208,8 @@ TIntermNode* TParseContext::handleReturnValue(const TSourceLoc& loc, TIntermType
     } else if (*currentFunctionType != value->getType()) {
         TIntermTyped* converted = intermediate.addConversion(EOpReturn, *currentFunctionType, value);
         if (converted) {
+            if (*currentFunctionType != converted->getType())
+                error(loc, "cannot convert return value to function return type", "return", "");
             if (version < 420)
                 warn(loc, "type conversion on return values was not explicitly allowed until version 420", "return", "");
             return intermediate.addBranch(EOpReturn, converted, loc);